Flags API (#9666)

* feat: new routes for flags API

+ flag get
+ flag creation, migration from socket method
+ flag update, migration from socket method
* fixed bug where you could not unassign someone from a flag

* feat: tests for new flags API

added missing files for schema update

* fix: flag tests to use Write API instead of sockets

* feat: flag notes API + tests

* chore: remove debug line

* test: fix breaking test on mongo

src/api/index.js

@@ -6,4 +6,5 @@ module.exports = {
 	topics: require('./topics'),
 	posts: require('./posts'),
 	categories: require('./categories'),
+	flags: require('./flags'),
 };